//
// Created by next on 2022/4/7.
//

#include <functional>
#include <iostream>

struct Foo {
    Foo(int num) : num_(num) {}

    void print_add(int i) const { std::cout << num_ + i << '\n'; }

    int num_;
};

void print_num(int i) {
    std::cout << i << '\n';
}

struct PrintNum {
    void operator()(int i) const {
        std::cout << i << '\n';
    }
};

int main() {
    // store a free function
    std::function<void(int)> f_display = print_num;
    f_display(-9);

    // store a lambda
    std::function<void()> f_display_42 = []() { print_num(42); };
    f_display_42();

    // store the result of a call to std::bind
    std::function<void()> f_display_31337 = std::bind(print_num, 31337);
    f_display_31337();

    // store a call to a member function
    std::function<void(const Foo &, int)> f_add_display = &Foo::print_add;
    const Foo foo(314159);
    f_add_display(foo, 1);

    // store a call to a member function and object
    using std::placeholders::_1;
    std::function<void(int)> f_add_display2 = std::bind(&Foo::print_add, foo, _1);
    f_add_display2(2);

    // store a call to a member function and object ptr
    std::function<void(int)> f_add_display3 = std::bind(&Foo::print_add, &foo, _1);
    f_add_display3(3);

    // store a call to a function object
    std::function<void(int)> f_display_obj = PrintNum();
    f_display_obj(18);
}